I think it wouldn't be constitutional on the same grounds as Citizens United, namely, it would be a violation of the right to free speech. If I have a constitutional right as an individual to label things kosher or halal, why would I lose that right if I go into business with some friends? (I'm assuming I have this right as an individual, right?)

I think it is a consistent view that I do lose that right when I incorporate to be clear, and you could probably design a coherent society on that model - I just don't totally follow why / what the constitutional grounds are.

YOU don't lose that right, but the corporation is never given that right

What's the difference, in practice? Not only can the corporation fire me for putting such a label on the food, they must, if such a law exists - if they don't, they're liable.

So, let's say I'm a baker selling, I dunno, kosher cookies. I can sell them to my friends and say, "By the way, these are kosher!" They're popular with my friends, and so I decide to make a business out of it. As soon as I do that, the business is never given the right of free speech, and the business is now given an obligation to prevent me-the-individual from saying certain things in the course of my job duties. That is, if I continue saying the same thing I said yesterday, the government can shut down my business.

You'd say that this is constitutional?